C# - Lock Thread.sleep Not Working With .NET Thread?

Jun 25, 2010

I have a password page and when someone enters an incorrect password I want to simply foil a brute force attack by having

bool isGoodPassword = (password == expected_password);

lock (this)
{
if (!isGoodPassword)
Thread.Sleep(2000);
}
I would expect that this would allow all correct passwords without stalling, but if one user enters a bad password another successful password from a different user would also be blocked. However, the lock doesn't seem to lock across ASP.NET threads.

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